Background: Ondansetron is a serotonin 3 receptor antagonist widely used to prevent nausea and vomiting in pregnancy and in patients receiving chemotherapy. There is growing evidence that adjunctive ondansetron treatment improves symptomatology associated with schizophrenia, particularly with respect to the positive, negative and cognitive symptoms. Further studies that are applicable to real world practice are required to assess the efficacy and effectiveness of this treatment, which could be readily and rapidly translated into clinical practice.
Aims: This randomized control trial compared adjunctive (8 mg/daily) ondansetron or placebo to commonly prescribed atypical antipsychotics for people suffering with chronic schizophrenia ( ClinicalTrials.gov NCT01121042).
Methods: The study involved 85 outpatients aged 18-65 years with a diagnosis of schizophrenia or schizoaffective disorder who participated in a two-arm randomized control trial.
Results: Longitudinal analyses revealed adjunctive ondansetron provided significant improvement in the cognitive domain ( p<0.05) as measured by the Positive and Negative Syndrome Scale between baseline and week 12. The analysis of "Combination" showed ondansetron effect on Total Positive and Negative Syndrome Scale, approaching significance by week 12 ( p=0.06). No group differences were obtained in the Montgomery-Asberg Depression Rating Scale or Positive and Negative Syndrome Scale subscales.
Conclusion: This treatment trial provides some support for adjunctive ondansetron medication as a treatment for the cognitive disorganization symptoms of schizophrenia.
Keywords: Schizophrenia; adjunctive treatment; ondansetron; serotonin 3 receptor antagonist.